Loudspeaker overload protection

Abstract

A loudspeaker overload protection circuit and method receives at a compressor a signal representing the estimated loudspeaker power consumption; receives at the compressor a signal representing the nominal power of the loudspeaker; receives at the compressor an input audio signal from the signal source and supplying with the compressor an output audio signal to the loudspeaker; estimates from the output audio signal, (a) signal(s) that represent(s) the voltage and / or current supplied to the loudspeaker and a parameter that represents the ohmic resistance of the loudspeaker the power consumed by the loudspeaker; supplies a signal representing the estimated loudspeaker power consumption to the compressor; and attenuates the input audio signal when the signal representing the estimated loudspeaker power consumption exceeds the signal representing the nominal power of the loudspeaker.

Description

1. CLAIM OF PRIORITY[0001]This patent application claims priority from EP Application No. 12 156 566.7-2225 filed Feb. 22, 2012, which is hereby incorporated by reference.2. FIELD OF TECHNOLOGY[0002]This invention relates to a circuit and method for protecting loudspeakers, and more particularly to sensing an overload condition in the input signal of a loudspeaker and limiting input signal accordingly.3. RELATED ART[0003]In recent years switched audio amplifiers employing pulse width modulation (PWM) have become increasingly popular because they provide high power output with little heat dissipation so that even amplifiers with small dimensions can provide high levels of power for common loudspeakers. In order to avoid damages to the loudspeakers caused by the increased power supplied to them, limiters are used that limit the power to a tolerable value. However, limiting the power deteriorates the acoustic performance of the audio system (amplifier loudspeaker system) by, e.g., gene...

AI Technical Summary

Benefits of technology

The patent describes a circuit and method for protecting loudspeakers from overload damage. It uses a compressor to estimate the power consumed by the loudspeaker based on signals that represent the voltage and current supplied to it. When the estimated power consumption exceeds a predetermined limit, the compressor automatically attenuates the input audio signal to prevent damage to the loudspeaker. This technology is effective in protecting loudspeakers from excessive power consumption and can help to prolong their lifespan.

Problems solved by technology

However, limiting the power deteriorates the acoustic performance of the audio system (amplifier loudspeaker system) by, e.g., generating harmonic and non-harmonic distortions or by compressing the sound perceived by a listener to an unpleasant extent.

However, such limiters are often complex and require a great amount of detailed data of the loudspeaker for its modeling and, thus, are costly and difficult to implement.

Simple systems, in contrast, often deteriorate the acoustic performance of the system to an unacceptable extent.

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